In related art, a projector including a light source and a projection optical device that modulates light output from the light source, forms an image in response to image information, and enlarges and projects the image on a projection surface of a screen or the like is known.
Incidentally, as the light source employed for the projector, a configuration including an arc tube such as a high-pressure mercury lamp is known. The arc tube has a light emitting part having a nearly spherical shape, and a pair of sealed parts extending from both ends of the light emitting part in directions away from each other. When the arc tube is turned on, the temperature of the upper end portion of the light emitting part in the vertical direction becomes higher and the temperature of the lower end portion becomes lower than that of the upper end portion. Further, when the high-temperature state of the upper end portion of the light emitting part continues, denitrification is likely to occur, and, on the other hand, when the temperature difference between the upper end portion and the lower end portion is larger, blackening is likely to occur and the arc tube is easily deteriorated.
For the problem, a projector including a light source adapted to guide cooling air to the upper end portion even when the projector is mounted in either position of a normal position (stationary position) with the bottom part of the projector directed downward or an inverted position (hanging position) vertically inverted with respect to the normal position is proposed (for example, see PTL 1).